Apparatus selectively responsive to bilevel bipolar pulses

ABSTRACT

1. In a wire guided torpedo system of the type comprising a torpedo, a remote command transmitter for generating low and high-pulse D.C. command signals, a guidance receptor carried by the torpedo and having a pair of input terminals, a transmission line comprising a guidance wire and seawater return for communicating said command signals to said terminals and imposing distortions upon said command signals as received at said terminals, and utilization apparatus controllable by said guidance receptor, THE IMPROVEMENTS, IN COMBINATION, WHEREIN SAID GUIDANCE RECEPTOR IS CONSTRUCTED AND ARRANGED TO BE SELECTIVELY RESPONSIVE TO SAID COMMAND SIGNALS DESPITE SAID DISTORTIONS, COMPRISING: A. A FIRST COMMAND SIGNAL CHANNEL CONNECTED TO SAID INPUT TERMINALS AND COMPRISING A FIRST RELAY, AND A ZENER BREAKDOWN DIODE FOR EFFECTING ENERGIZATION OF SAID RELAY ONLY UPON RECEPTION OF A HIGH-PULSE COMMAND SIGNAL; B. A SECOND COMMAND SIGNAL CHANNEL COMPRISING A SECOND RELAY, AND MEANS FOR EFFECTING ENERGIZATION OF SAID SECOND RELAY UPON RECEPTION OF A LOW-PULSE COMMAND SIGNAL; C. SAID SECOND COMMAND SIGNAL CHANNEL BEING CONNECTED TO SAID INPUT TERMINALS THROUGH A NORMALLY CLOSED SWITCH CONTROLLED BY SAID FIRST RELAY; AND D. MEANS FOR PREVENTING OPERATION OF SAID SECOND RELAY DURING PULSE RISE TIME OF SAID HIGH-PULSE COMMAND SIGNAL.

Unite States i [191 Martin et a1.

[ July 29, 1975 Anthony J. Muscante, Baltimore, both of Md.

[73] Assignee: United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: May 5, 1964 [21] Appl. No.: 365,571

Primary Examiner-Stephen C. Bentley Attorney, Agent, or FirmRichard S. Sciascia; Ervin F. Johnston EXEMPLARY CLAIM 1. In a wire guided torpedo system of the type comprising a torpedo, a remote command transmitter for generating low and high-pulse D.C. command signals, a guidance receptor carried by the torpedo and having a pair of input terminals, a transmission line comprising a guidance wire and seawater return for communicating said command signals to said terminals and imposing distortions upon said command signals as received at said terminals, and utilization apparatus controllable by said guidance receptor,

the improvements, in combination, wherein said guidance receptor is constructed and arranged to be selectively responsive to said command signals despite said distortions, comprising:

a. a first command signal channel connected to said input terminals and comprising a first relay, and a Zener breakdown diode for effecting energization of said relay only upon reception of a high-pulse command signal;

b. a second command signal channel comprising a second relay, and means for effecting energization of said second relay upon reception of a low-pulse command signal;

c. said second command signal channel being connected to said input terminals through a normally closed switch controlled by said first relay; and

(1. means for preventing operation of said second relay during pulse rise time of said high-pulse command signal.

4 Claims, 2 Drawing Figures 1Q l2 A UTILIZATION J5 H APPARATUS COMMAND TRANSMISSION comm/um TRANSMITTER LINE RECEIVER l UTILIZATION l 1 APPARATUS T T STE NE PATENTEB JULZSIS'IS cc 0 c DR NE w E 1 Mo 0.... CR 0 4 6 I? Ill: N m s SE MN 1 2\\N.. A II R T. 5 K R E T n MM \um m R T.

E T. 2 \lfiv 4 .i O 2 5 4 6 F 4 Q 9 9 9 9 i m m l 4. L 1\ WQ 0 wmms mwnw EH! 5 5 E LR 7 6 4 7 F N M A l 2 2 2 3 2 Y 5 2 @v /%A..% I: E 1i I l .4 M 8 TIM 8 8 W HTIIVW,IIN T T W N. a A J R 0 7 E N H .3 B T N R JA FIG. 2.

A 6 SOURCE APPARATUS SELECTIVELY RESPONSIVE TO BILEVEL BIPOLAR PULSES The invention relates generally to singal responsive apparatus and more paticularly to an apparatus selectively responsive to multi-level DC pulse signals.

The present invention is directly intended for use in connection with so-called wire-guided torpedo systems and will therefore be described principally with reference to such application. In wire-guided torpedo systems, the torpedo is designed to be controlled (e.g. to change course and detonation instant, or to accomplish any other desired functions) by post-launch command signals sent via a transmission line type of communication link comprising an insulated wire (and seawater return) extending from a control station carried by the launching vessel to a guidance receptor carried by the torpedo. The insulated wire, hereinafter termed a guidance wire, is paid out from a coil forming part of a dispenser carried by the torpedo; another wire dispenser may be carried by the launching vessel in order to accommodate vessel maneuvers, after torpedo launch, without breaking the communication link. The wire coils are to be understood as forming part of the transmission line, and are presently provided in the form of hollow-core layer-wound construction to permit smooth payout of wire from the center, the payout ends of the torpedo-carried and vessel-carried coils being spliced and hermetically sealed. In practice, the total length of guidance wire in the communication link may be of the order of 15000 yards.

The guidance receptor must of course be selectively responsive to the command signals with accuracy and reliability despite waveform distortion and other disturbances experienced by the command signals as a result of transmission line effects and their changing magnitudes during the course of a torpedo run. Because command signal disturbances and guidance receptor response problems are particularly aggravated in the case of command signals of DC pulse type, wire-guided torpedo systems and guidance receptors heretofore have been designed for use with AC command signals, requiring transmission and reception at several different frequencies. The use of DC pulse command signals and a guidance receptor for use therewith would otherwise be preferable, however, because of such reasons as simplification of equipment both in the command transmitter and command receiver, with resultant lower cost and reduced space requirements.

It is an object of the invention to provide a DC pulse command signal transmission and reception system including a command receiver having novel circuitry and yielding improved accuracy and reliability of command signal response.

It is another object of the invention to provide a command receiver selectively responsive to bipolar, multilevel DC pulse command signals.

It is a further object of the invention to provide a command receiver selectively responsive to multi-level DC pulse command signals and reliably operative under conditions of pulse waveform distortions imposed by a communication link.

Other objects, advantages and novel features of the invention will become apparent as the same becomes better understood by reference to the following description when considered in conjunction with the accompanying drawing wherein:

FIG. 1 illustrates generally and schematically the major elements of an illustrative command signal system embodying the present invention; and

FIG. 2 illustrates the basic elements and circuitry of a novel command receiver in accordance with the present invention.

Referring first to the FIG. 1 block diagram, the command signal transmission and reception system here shown comprises a command transmitter 10, a command receiver 11, a communication link 12 therebetween which, when taking the form of a long transmission line, causes serious distortion of pulse signal waveform in a manner which renders conventional command receivers unreliable in their response, and utilization apparatus 13 and 14 each having two operational conditions or directions of adjustment selectively controlled by command receiver 11 in accordance with command signal characteristics. In the case of a typical wire-guided torpedo system, command transmitter 10 forms part of the fire control system carried by the torpedo-firing submarine or other launching vessel; under control by an operator and in accordance with decisions involving knowledge of both target and torpedo locations, command transmitter 10 provides DC pulse command signals characterized by positive and negative polarities and two different nominal amplitudes; transmission line 12 comprises a guidance wire, connected between leads 15 and 16, and a seawater return path represented by the ground symbols; command receiver 11 when forming part of a wire-guided torpedo is specifically termed a guidance receptor; utilization apparatus 13 and 14 may be designed for incremental control of any two functions, e.g. change in course to port or to starboard, and advancement or retardation of warhead detonation instant.

Command receiver 11, detailed in FIG. 2, functions to convert the DC pulse command signals applied to input terminal 20 (relative to input terminal 21) into control functions by selective energization of the four relays 22, 23, 24 and 25. The DC pulse command signals may have nominal magnitudes of say i 45 volts and :1: 160 volts, and the resultant four types of pulses are referred to hereinafter simply as positive high, positive low, negative high and negative low pulses. The input pulses may be transmitted at a rate of say 4 per second, may each have a nominal duration of say milliseconds, and as a result of transmission line effects may exhibit pulse rise and pulse decay times of the order of 10 milliseconds, in addition to oscillatory transients. By reason of the circuit combinations to be described, command receiver ll reliably discriminates the four types of command signals and maintains energization of the proper relay during each pulse period without spurious energization of any other relay.

While any filtered DC power supply would be suitable for use in energizing the illustrated circuit, a highefficiency electrical power supply as illustrated is preferable, supplying pulsating DC power without filtering, causing ripple in the circuit currents but without interference to circuit operation. With AC source 30 operating at say 400 cycles per second, supplying power to transformer 31 employed in a full-wave rectification arrangement comprising the center-tapped secondary and diodes 32 and 33, the voltage supplied to points 34 and 35 consists of pulses occurring at 1.25 millisecond intervals, intervals which are sufficiently short not to interfere with relay pull-in and hold-in action during a command pulse period. Resistors 36, 37 serve as a voltage divider to suitably reduce the voltage as applied to the collectors of transistors 38 and 39.

The positive high-pulse switching circuit comprises relay 22, zener diode 40, diode 41 and NPN transistor 42; the positive low-pulse switching circuit comprises relay 23, resistors 43 and 44, diode 45, NPN transistors 38 and 46, and resistors 47, 48 and 49. Similarly, the negative high-pulse switching circuit comprises relay 25, zener diode 50, diode 51 and'NPN transistor 52; and the negative low-pulse switching circuit comprises relay 24, resistors 53 and 54, diode 55, NPN transistors 39 and 56, and resistors 48, 49 and 57.

Polarity sensing is achieved principally by the diodes 60, 61 connected in opposed relationship between the input terminals 20, 21. E.g., during application of a positive pulse signal to terminal 20, diode 61 presents comparatively low resistance since the applied command signal is in the forward conduction direction of the diode, substantially the entire voltage of the positive command pulse thus appearing across diode 60 and across the input lines to the positive pulse switching circuits. The action is reversed upon application of a negative pulse signal. Suitably-poled blocking diodes 41, 45 and 51, 55 in the positive and negative pulse switching circuits, respectively, serve to insure proper and complete channeling of the positive and negative pulse command signals applied to input terminal 20.

First considering operation of the circuit during application of positive pulse command signals, these signals initially appear at the input lines of both the positive high and low-pulse switching circuits. The highpulse circuit path extends from terminal 20 through zener diode 40 and diode 41 to transistor 42 and the relay 22 controlled thereby. The low-pulse circuit path extends from terminal 20 through the arm and upper contact of switch 62 of de-energized relay 22, the voltage divider comprising resistors 43 and 44, and diode 45, to transistors 38 and 46 and the relay 23 controlled thereby. Inclusion of resistor 43 between input terminal 20 and diode 45 (through switch 62 of relay 22) is essential to enable breakdown of zener diode 40 during application of a positive high-pulse to both the lowpulse and high-pulse switching circuits.

When a positive high-pulse is received, the pulse voltage appears across the loop circuit comprising zener diode 40, diode 41, base-to-emitter circuit of transistor 42, and resistors 48 and 49, resistor 49 being of comparatively low value relative to resistor 48. Because of the comparative resistance values involved, however, voltage magnitude sensing of the positive high-pulse is achieved principally as a result of division of voltage between zener diode 40 and resistor 48. As the positive high-pulse command signal rises to a voltage greater than that which operates the low-pulse switching circuit, but before relay 23 in the latter circuit can react because of the time delay imposed by the use of shunting capacitor 83, zener diode 40 breaks down due to avalanche effect and begins to pass current; as the command signal increases toward its nominal level, the increased current in the loop circuit including zener diode 40 results in a bias voltage, principally across resistor 48, high enough to cutoff or reduce the base current in transistor 38, and correspondingly reduce the collector current in transistor 46, to values below that necessary for energization of relay 23. While cutoff of the low-pulse switching circuit is principally a result of the bias developed across resistor 48 by the high-pulse current during the high-pulse rise time, it is made to occur at lower values of the high-pulse command signal by inclusion of resistor 49 since the latter resistor, being in the coil current circuit of relay 22, provides additional bias voltage. At such time, also, the base-toemitter current in transistor 42, and correspondingly the collector current, become large enough to result in energization of relay 22 after a short time interval imposed by the use of capacitor 82 shunting the coil of relay 22. Such use of capacitor 82 serves to prevent momentary operation of relay 22 by pulse transients, such as an oscillatory rise of voltage in a low-pulse command signal. Relay 22 thus becomes energized without transient energization of relay 23, and switch 62 at this time operates to break continuity of the input to the low-pulse switching circuit. At this time, also, operation of switch 62 shorts out zener diode 40, causing conduction of transistor 42 and energization of relay 22 to continue for a portion of the high-pulse decay time; further, the shunting capacitor 82 functions to increase the hold-in time of relay 22; these two effects coact to maintain relay 22 energization and consequently disconnection of the input to the low-pulse switching circuit until the high-pulse command signal has decayed to a voltage level below the operating point of the lowpulse switching circuit. Energization of relay 22, in response to the positive high-pulse command signal, operates switch 72, establishing continuity from terminal to terminal 91, which can be employed to provide one operational condition of associated utilization apparatus (13, FIG. 1).

Next considering operation of the circuit during application of a positive low-pulse command signal, such signal (except for the transient oscillatory voltage rise problem which is overcome by the use of capacitor 82 as has been described) is of insufficient amplitude to cause breakdown of zener diode 40, and the low-pulse command signal is thus excluded from the high-pulse switching circuit. The positive low-pulse signal is coupled, through the normally closed contacts of switch 62 of relay 22, to the voltage divider comprising resistors 43 and 44, and through diode 45 to the base-to-emitter circuit of transistor 38. Resistor 47 in the base circuit provides a path for leakage current in transistor 38 and prevents this current from being amplified and coupled to transistor 46. The emitter current of transistor 38 flows through the base-to-emitter circuit of transistor 46, and the resultant collector current of transistor 46 causes energization of relay 23. As already described, capacitor 83 connected in parallel with the winding of relay 23 imposes a time delay which assists in preventing relay 23 operation during the voltage rise transient of the positive high-pulse command signal. When relay 23 is energized in response to the positive low-pulse command signal, switch 73 is operated, establishing continuity from terminal 90 to terminal 92 which can be employed to provide another operational condition of the associated utilization apparatus (13, FIG. 1).

Operation of the circuit during application of negative pulse command signals is entirely similar to that already described for the positive pulse command signals, since a so-called back-to-back symmetrical arrangement is provided. The windings of relays 24 and 25 in the negative low-pulse and high-pulse switching circuits are shunted by capacitors 84 and 85, respectively, for the same reasons as given with reference to the shunting capacitors in the positive low-pulse and high-pulse switching circuits. Energization of the relay in response to a negative high-pulse command signal operates to break continuity of the input to the negative low-pulse switching circuit, and further shorts out zener diode 50,through action of switch 65; simultaneous operation of switch 75 establishes continuity from terminal 94 to terminal 96 which can be employed to provide an operational condition of associated utilization apparatus (14, FIG. 1). Energization of the relay 24 in response to the negative low-pulse command signal operates switch 74, establishing continuity from terminal 94 to terminal 95 which similarly can be employed to provide another operational condition of the associated utilization apparatus (14, FIG. 1).

The following table lists designations or nominal values of circuit components which have been found to provide entirely satisfactory operation of command receiver 11, in a wire-guided torpedo system in which i 45 volt and i 160 volt command pulses, as described, are transmitted over a guidance wire (seawater return) transmission line having a total length of about 15,000 yards and presenting approximately 1300 ohms series resistance, in association with a command receiver power supply delivering an 800 cps pulsating voltage, as described, at about 72 volts (peak value) to point 34 relative to point 35 in command receiver 11. Employing such components, the command receiver has been found to present a resistive input impedance of about 22000 ohms of 45-volt pulse operation, about 15,000 ohms to l60-volt pulses before operation of the high pulse relay (22 or 25, FIG. 2), and about 25,000 ohms after such relay operation.

Diodes 41, 51, 60, 61 1N649, quad Zener diodes 40, 5O SV4022A, 22 volts at 1 ma. Transistors 38, 39 2N343 Transistors 42,46,52,56 2N657/C Resistors 36, 37 1000 ohms 43, 53 6800 ohms 44, 54 24000 ohms 47, 57 56000 ohms 48 22000 ohms 49 150 ohms Relays 22,23,24,25 General purpose, DPDT, 26.5

volts, 400 ohms 25 microfarads Capacitors 82, 85

microfarads Capacitors 83, 84

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a wire guided torpedo system of the type comprising a torpedo, a remote command transmitter for generating low and high-pulse D.C. command signals, a guidance receptor carried by the torpedo and having a pair of input terminals, a transmission line comprising a guidance wire and seawater return for communicating said command signals to said terminals and imposing distortions upon said command signals as received at said terminals, and utilization apparatus controllable by said guidance receptor,

the improvements, in combination, wherein said guidance receptor is constructed and arranged to be selectively responsive to said command signals despite said distortions, comprising:

a. a first command signal channel connected to said input terminals and comprising a first relay, and a zener breakdown diode for effecting energization of said relay only upon reception of a high-pulse command signal;

b. a second command signal channel comprising a second relay, and means for effecting energization of said second relay upon reception of a low-pulse command signal;

c. said second command signal channel being connected to said input terminals through a normally closed switch controlled by said first relay; and

d. means for preventing operation of said second relay during pulse rise time of said high-pulse command signal.

2. A combination as defined in claim 1, wherein said last-named means comprises a capacitor shunting the winding of said second relay to provide relay energization delay.

3. A combination as defined in claim 2, wherein said firstnamed means comprises an amplifier for effecting energization of said second relay upon reception of a low-pulse command signal, said amplifier having a cutoff biasing circuit responsive to development of zener diode breakdown current in said first command signal channel, and said capacitor and biasing circuit coacting to prevent energization of said second relay during pulse rise time of said high-pulse command signal.

4. A combination as defined in claim 1, further comprising means for delaying dropout of said first relay until said high-pulse command signal decays to a value lower than that necessary for operation of said second command signal channel. 

1. In a wire guided torpedo system of the type comprising a torpedo, a remote command transmitter for generating low and high-pulse D.C. command signals, a guidance receptor carried by the torpedo and having a pair of input terminals, a transmission line comprising a guidance wire and seawater return for communicating said command signals to said terminals and imposing distortions upon said command signals as received at said terminals, and utilization apparatus controllable by said guidance receptor, the improvements, in combination, wherein said guidance receptor is constructed and arranged to be selectively responsive to said command signals despite said distortions, comprising: a. a first command signal channel connected to said input terminals and comprising a first relay, and a zener breakdown diode for effecting energization of said relay only upon reception of a high-pulse command signal; b. a second command signal channel comprising a second relay, and means for effecting energization of said second relay upon reception of a low-pulse command signal; c. said second command signal channel being connected to said input terminals through a normally closed switch controlled by said first relay; and d. means for preventing operation of said second relay during pulse rise time of said high-pulse command signal.
 2. A combination as defined in claim 1, wherein said last-named means comprises a capacitor shunting the winding of said second relay to provide relay energization delay.
 3. A combination as defined in claim 2, wherein said firstnamed means comprises an amplifier for effecting energization of said second relay upon reception of a low-pulse command signal, said amplifier having a cut-off biasing circuit responsive to development of zener diode breakdown current in said first command signal channel, and said capacitor and biasing circuit co-acting to prevent energization of said second relay during pulse rise time of said high-pulse command signal.
 4. A combination as defined in claim 1, further comprising means for delaying dropout of said first relay until said high-pulse command signal decays to a value lower than that necessary for operation of said second command signal channel. 